import { DocumentNode, TextBlock, TextImage, TextSegment, TextStyle, TextTable } from './types';
export type { ImageStyle, TextBlock, TextBlockType, TextImage, TextSegment, TextStyle, TextTable, TextTableCell, TextTableRow } from './types';
export interface LayoutCursor {
    segmentIndex: number;
    graphemeIndex: number;
}
export interface RichInlineItem {
    text: string;
    font: string;
    letterSpacing?: number;
    break?: 'normal' | 'never';
    extraWidth?: number;
}
export interface PreparedRichInline {
    readonly __preparedRichInlineBrand?: true;
}
export interface RichInlineFragmentRange {
    itemIndex: number;
    gapBefore: number;
    occupiedWidth: number;
    start: LayoutCursor;
    end: LayoutCursor;
}
export interface RichInlineLineRange {
    fragments: RichInlineFragmentRange[];
    width: number;
    end: {
        itemIndex: number;
        segmentIndex: number;
        graphemeIndex: number;
    };
}
export interface PreparedTextBlock {
    prepared?: PreparedRichInline;
    itemSegmentIndexes: readonly number[];
    block: TextBlock;
}
export interface PreparedText {
    segments: readonly TextSegment[];
    blocks: readonly PreparedTextBlock[];
    baseStyle: Required<Pick<TextStyle, 'fontFamily' | 'fontSize' | 'lineHeight'>>;
    lineHeight: number;
}
export interface PrepareOptions {
    baseStyle?: TextStyle;
}
export interface ExtractDocumentBlocksOptions {
    coverImageSrcs?: readonly string[];
}
export interface LayoutOptions {
    inlineSize: number;
    lineHeight?: number;
    blockStart?: number;
    blockGap?: number;
    maxBlockHeight?: number;
}
export interface LinePosition {
    segmentIndex: number;
    cursor: LayoutCursor;
}
export interface LineSegmentRange {
    segmentIndex: number;
    start: LayoutCursor;
    end: LayoutCursor;
    text: string;
    style: TextStyle;
    source?: TextSegment['source'];
    gapBefore: number;
    occupiedWidth: number;
}
export interface LineRange {
    index: number;
    kind: 'text' | 'image' | 'table' | 'separator' | 'pre';
    block?: TextBlock;
    image?: TextImage;
    table?: TextTable;
    start: LinePosition | null;
    end: LinePosition | null;
    text: string;
    width: number;
    top: number;
    height: number;
    inlineOffset?: number;
    segments: readonly LineSegmentRange[];
}
export interface VisibleLineWindow {
    startIndex: number;
    endIndex: number;
    offsetTop: number;
    totalHeight: number;
    lines: readonly LineRange[];
}
export interface CanvasProviderLike {
    createOffscreenCanvas?(options?: {
        type?: string;
        width?: number;
        height?: number;
    }): {
        getContext(type: '2d'): PretextMeasureContext | null;
    };
}
export interface PretextMeasureContext {
    font: string;
    measureText(text: string): {
        width: number;
    };
}
export interface PretextMeasurementPolyfillOptions {
    /**
     * Install an estimated text measurer when the host cannot provide a native
     * offscreen canvas. This keeps layout usable with less exact line breaks.
     */
    estimatedFallback?: boolean;
}
/**
 * Installs the canvas shape expected by @chenglou/pretext in runtimes where
 * OffscreenCanvas is exposed by a host adapter instead of as a browser global.
 */
export declare function installPretextMeasurementPolyfill(canvasProvider?: CanvasProviderLike, options?: PretextMeasurementPolyfillOptions): boolean;
export declare function extractDocumentSegments(nodes: readonly DocumentNode[], baseStyle?: TextStyle, options?: ExtractDocumentBlocksOptions): TextSegment[];
export declare function extractDocumentBlocks(nodes: readonly DocumentNode[], baseStyle?: TextStyle, options?: ExtractDocumentBlocksOptions): TextBlock[];
export declare function prepare(segments: readonly TextSegment[], options?: PrepareOptions): PreparedText;
export declare function prepareBlocks(textBlocks: readonly TextBlock[], options?: PrepareOptions): PreparedText;
export declare function layout(prepared: PreparedText, options: LayoutOptions): LineRange[];
export declare function getVisibleLines(lines: readonly LineRange[], scrollTop: number, viewportHeight: number, overscan?: number): VisibleLineWindow;
export type PretextRichInlineLineRange = RichInlineLineRange;
//# sourceMappingURL=pretext.d.ts.map